Absolute value in awk doesn't work?

Question

I want to select line of a file where the absolute value of column 9 is less than 500. Column is sometimes positive, sometimes negative.

awk -F\'\\t\' \'{ if         


        

Answer 1

There is a loss of precision using sqrt($9^2). That might be a problem if you want to print the absolute value as well.

Solution: process as text, and simply remove the leading minus sign, if present.

This guarantees that the output matches the input exactly.

Code:

awk '{sub("^-", "", $9); if ($9 < 500) print $9}' inputfile

Summary: to get absolute value using awk, simply remove the leading minus (-) character from a field, if present.